Pandas Multiply 2D by 1D Dataframe
Question:
Looking for an elegant way to multiply a 2D dataframe by a 1D series where the indices and column names align
df1 =
Index
A
B
1
1
5
2
2
6
3
3
7
4
4
8
df2 =
Coef
A
10
B
100
Something like…
df3 = df1.mul(df2)
To get :
Index
A
B
1
10
500
2
20
600
3
30
700
4
40
800
Answers:
There is no such thing as 1D DataFrame, you need to slice as Series to have 1D, then multiply (by default on axis=1):
df3 = df1.mul(df2['Coef'])
Output:
A B
1 10 500
2 20 600
3 30 700
4 40 800
If Index is a column:
df3 = df1.mul(df2['Coef']).combine_first(df1)[df1.columns]
Output:
Index A B
0 1.0 10.0 500.0
1 2.0 20.0 600.0
2 3.0 30.0 700.0
3 4.0 40.0 800.0
Looking for an elegant way to multiply a 2D dataframe by a 1D series where the indices and column names align
df1 =
| Index | A | B |
|---|---|---|
| 1 | 1 | 5 |
| 2 | 2 | 6 |
| 3 | 3 | 7 |
| 4 | 4 | 8 |
df2 =
| Coef | |
|---|---|
| A | 10 |
| B | 100 |
Something like…
df3 = df1.mul(df2)
To get :
| Index | A | B |
|---|---|---|
| 1 | 10 | 500 |
| 2 | 20 | 600 |
| 3 | 30 | 700 |
| 4 | 40 | 800 |
There is no such thing as 1D DataFrame, you need to slice as Series to have 1D, then multiply (by default on axis=1):
df3 = df1.mul(df2['Coef'])
Output:
A B
1 10 500
2 20 600
3 30 700
4 40 800
If Index is a column:
df3 = df1.mul(df2['Coef']).combine_first(df1)[df1.columns]
Output:
Index A B
0 1.0 10.0 500.0
1 2.0 20.0 600.0
2 3.0 30.0 700.0
3 4.0 40.0 800.0